One hundred asthmatic children who are allergic to cockroaches will be recruited from the Johns Hopkins Pediatric Allergy clinics. Qualifying children will enter a Baseline Phase during which they will undergo an initial evaluation of symptoms, skin testing, spirometry and methacholine challenge testing. Sera will be colledted for IgE and IgG antibody to cockroach. A home visit will be performed to assess roach infestation, and to measure indoor allergens in settled dust. At the end of 2 months the child and their family will enter the Treatment Phase. Fifty families will be randomly selected to receive active treatment (insecticide, mattress covers and commercial cleaning) and 50 controls will receive no treatment until the completion of the trial. Bimonthly clinic visits will continue for the next 6 months. Home visits will continue every other month to inspect, set roach sticky trap samplers and collect household dust for allergen analysis. We therefore propose to examine the effect of cockroach and cleaning on asthma morbidity in children living in the inner city of Baltimore.